Bi-polymer thermoplastic

ABSTRACT

A braided thermoplastic ribbon is disclosed having fully impregnated filaments. The ribbon is formed by a thermoplastic prepreg having a plurality of continuous fibers that are substantially oriented in a longitudinal direction, the continuous fibers constituting from about 30 wt. % to about 40 wt. % of the prepreg, a first resinous matrix that contains a first set of one or more thermoplastic polymers and within which the continuous fibers are embedded, wherein the thermoplastic polymers constitute from about 30 wt. % to about 40 wt. % of the prepreg, and a second resinous matrix that contains a second set of one or more thermoplastic polymers, wherein the second set of thermoplastic polymers constitute from about 30 wt. % to about 40 wt. % of the prepreg.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/321,364 filed on Apr. 12, 2016; U.S. Provisional Application No.62/449,462 filed on Jan. 23, 2017; and U.S. Provisional Application No.62/473,468 filed on Mar. 19, 2017, all which are hereby incorporatedherein by reference.

TECHNICAL FIELD

This disclosure relates generally to composite materials, and moreparticularly to reinforced composite materials having a bi-polymerstructure.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Reinforced composite materials (or “prepregs”) have conventionally beenformed from fibers (e.g., carbon or glass fibers) that are impregnatedwithin either a thermoset or thermoplastic resinous matrix. Thermosetresins (e.g., unsaturated polyester, epoxy and polyimide) or,Thermoplastic Polymers (e.g., polyolefin's, polyesters, polyamide-imid,TPU's, polycarbonates, and other engineering thermoplastic polymers) areoften employed as the matrix, particularly in applications requiring ahigh level of strength.

In the area of thermoplastic composites there are three primary materialtypes (1) a short fiber reinforced thermoplastic; (2) a continuousreinforced thermoplastic; and (3) a long fiber reinforced thermoplastic(LFT). The short fiber reinforced thermoplastic is generally a pelletthat has been produced through traditional compounding technology, wherea reinforced fiber is added “dry”, in a chopped format to a twin screwextruder along with a thermoplastic polymer and additives. This mixtureis then extruded into a cord or rod, chilled and then pelletized. Thesepellets are primarily used in injection molding applications. Thesepellets allow for flow into complex molding shapes with some enhancedproperties due to the fiber addition and additives. The gain inproperties however is minimal due to the resulting short fiber length,and therefore the property enhancement achieved by these short fibers islimited.

In comparison, the continuous fiber reinforced thermoplastic product, inthe form of thermoplastic composite tapes, are compression or autoclavemolded into a thermoplastic composite part. The properties of theseparts are derived due to sustainable fiber lengths and controlledorientation of the fibers in the molding process. The molding processhowever, due to the continuous fiber length is limited to less complexshapes, and usually achieves lower production volumes.

The long fiber thermoplastic composite type was primarily developed toachieve the most beneficial aspects of the two aforementioned processes.The long fiber thermoplastic process produces a pellet where thereinforcing fiber length is the same length as the pellet. Thesereinforcing fibers have not been degraded in length by a twin screwcompounding process. These long fiber thermoplastic composite pelletsare produced by pulling a reinforcing strand, continuously, through amolten bath of polymer, where the fiber and polymer distribution iscontrolled. This strand is then cooled and chopped into a pellet wherethe fiber length is nominally between ¼″ and 1″ long. These pellets aresold to, or produced by, a thermoplastic composite molder throughseveral varying processes. Generally, these molding processes feed thepellets into a low sheer, reciprocating and single screw extruder. Theresulting extrudate is placed into a mold and then compression moldedunder very high pressure, into a composite part or article. Thisresulting part has the benefit of greatly enhanced reinforcement length,which results into a part that has superior modulus and strength, whilereducing shrinkage. This process also lends itself to short moldingcycles and high production volumes.

Long fiber thermoplastic types are limited by the types of polymers thatcan be used. The polymers that can be used are limited in choice bytheir viscosity profiles and the additives are limited to those that donot inhibit the impregnation of the reinforcing fibers. Due to the factthat the polymer is of a low viscosity nature, thus a low molecularweight version of that polymer, is needed to impregnate the reinforcedstrand. The resulting molded article will be limited in properties dueto that impregnation process. Generally, low molecular weight polymersdo not have the toughness or impact resistance of their higher molecularweight counter parts, therefore impact resistance is achieved from theresulting fiber length, not the polymer itself. If higher molecularweight polymers are used in the LFT impregnation process the result isslower speeds, lower volumes and poor whet-out of the fiber strand.Hence, the composite part generated from these higher molecular weightswould have higher costs, longer mold cycles and “dry” fibers, whichwould inhibit the mechanical properties. Therefore, there is a need fora composite material and manufacturing process to reduce theaforementioned deficiencies.

In packaging and shipping markets, consumer goods markets, fashionmarkets, home improvement markets various banding types may be usedincluding straps, ribbons, tapes, straps, bands, ropes, cords, strings,laces, various coilable products, etc., are known and utilized to holdproduct down during shipping. Various similar products are available onrecreational markets including, e.g., braided or woven tie downs frompolymer fibers. For heavy-duty applications where high tensile strengthis required, steel or metal banding is known. For lighter weightproduct, plastic banding is often utilized. The various known straps mayinclude some type of mechanical fastener. Known ribbons are generallyfound within the market of fabrics. They also can include low tensilestrength applications such as cinch straps and draw strings. Generally,ribbons tend to decorate, are sewn to or enclosed by another fabric.Known ribbons are woven from cotton, various threads or other fabricmaterial.

Binding products are also known including safety netting, aircraft andmarine tie downs, ratchet straps for trucking and marine applications.

In the tape product category, there are 3 primary known forms: (1) anunreinforced tape, containing only resin or polymer designed for sealingor binding envelopes, packages, pallets, etc. such as scotchtape{circumflex over ( )}TM via polymer strapping tape; (2) a “layered”tape having a layer of reinforcing fiber like cotton, polyester, orfiberglass fibers added to increase the tensile properties of the tapewhere a higher user demand is placed on the performance of the tape orstrapping; and (3) a “composite tape”. With respect to the “layered”tape category is important to note that the known reinforcements arelayered between the resins or polymers used and not encapsulated thereinor integrated thereof. The “composite tape” is formed where differentreinforcements, such as carbon, aramid, HDPE Fiber and fiberglass, arefully encapsulated in a resinous or polymer matrix. These compositetapes are then layered, in an engineered manner, placed undersignificant heat and pressure, and molded into parts such as boat hulls,one piece showers, automobile hoods, etc. Because of the expense inmaking these tapes and the time, temperature and pressure required tomake them bond to each other they are unsuitable for sealing or bindingapplications. All of these known variants of tape requires use of anadhesive to affix them to objects which they are meant to seal, repair,bind etc. The adhesive is a key component of the tape that is requiredfor its functionality and use.

Therefore, it would be advantageous to manufacture a thermoplasticribbon formable into a braided tube or sleeve, after applying a thermalenergy source, that does not require a layer of adhesive for attachment.

SUMMARY

A thermoplastic prepreg and methods for manufacturing same aredisclosed. The thermoplastic prepreg includes a plurality of continuousfibers constituting from about 60 wt. % to about 70 wt. % of theprepreg, a first resinous matrix that contains a first set of one ormore thermoplastic polymers and within which the continuous fibers areimpregnated, wherein the thermoplastic polymers constitute from about 30wt. % to about 40 wt. % of the prepreg, and a second resinous matrixthat contains a second set of one or more thermoplastic polymers,wherein the second set of thermoplastic polymers constitute from about30 wt. % to about 40 wt. % of the prepreg. This will provide an overallthermoplastic impregnated strand where the continuous fibers account for30 wt. % to 40 wt. % and the combined two thermoplastic polymer layersconstitute for 60 wt. % to 70 wt. % of the overall product. This strandwill then typically be pelletized into ⅛″ to 1″ lengths.

A braided thermoplastic ribbon is disclosed having a substantiallyimpregnated fiber embedded within a resinous matrix.

In various embodiments, the braided thermoplastic ribbon is formed intoa tube. The tube may then be heated and formed to an object or partiallyformed, as desired, as it cools.

In various embodiments, the braided thermoplastic ribbon may be used inmedical or dental applications. For example, the braided thermoplastictube disclosed herein will allow for the use without the need formechanical fasteners. Since the tube is not tacky at room temperature itcan be positioned or repositioned in to the exact manner that is needed.Even after heat has been applied and the products are sealed togetherthen subsequently cooled, as long as a “tag” end remains un-bonded, itcan be re-heated and unwound or removed.

In one embodiment, the braided thermoplastic tube, having lowtemperature, low pressure bonding properties, is formed using a polymerconfigured to bond primarily with itself.

This summary is provided merely to introduce certain concepts and not toidentify key or essential features of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 schematically shows an exemplary impregnation system, inaccordance with the present disclosure;

FIG. 2A shows a cross-section of a known reinforced composite materialafter polymer impregnation;

FIG. 2B shows a cross-section of a reinforced composite material after afirst stage of polymer impregnation, in accordance with the presentdisclosure;

FIG. 2C shows a cross-section of the reinforced composite material aftera second stage of polymer impregnation, in accordance with the presentdisclosure;

FIG. 3 shows and exemplary thermoplastic ribbon, in accordance with thepresent disclosure;

FIG. 4 is a cross-sectional view of the thermoplastic ribbon, inaccordance with the present disclosure;

FIGS. 5A-5F show various thermoplastic ribbons and exemplaryapplications, in accordance with the present disclosure;

FIG. 6A-6C show an exemplary thermoplastic sleeve placed over an object,in accordance with the present disclosure; and

FIGS. 7A and 7B show exemplary tubes with enlarged areas illustratingbraids of the tube, in accordance with the present disclosure.

DETAILED DESCRIPTION

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the subject matter of thepresent disclosure. Appearances of the phrases “in one embodiment,” “inan embodiment,” and similar language throughout this specification may,but do not necessarily, all refer to the same embodiment.

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentdisclosure.

Generally, the present disclosure is directed to a prepreg that containstwo separate and discrete layers whereas the first layer contains aplurality of unidirectionally aligned continuous fibers embedded withinthe first polymer. Through such layering, polymer properties of thefirst and second layers may be augmented, and/or complimented accordingto an intended application. Although unique polymer combinations andstructure are one aspect of the present disclosure, it should beunderstood that fiber properties, fiber types, and fiber structure mayalso be adapted. In fact, one notable feature of the present disclosureis the ability to tailor the mechanical properties of the prepreg for anintended application by selectively controlling certain processparameters, such as the type of continuous fibers employed, theconcentration of the continuous fibers, along with the thermoplasticresins used for each of the layers.

Various embodiments of the present disclosure will be described indetail with reference to the drawings, where like reference numeralsrepresent like parts and assemblies throughout the several views.Reference to various embodiments does not limit the scope of thedisclosure, which is limited only by the scope of the claims attachedhereto. Additionally, any examples set forth in this specification arenot intended to be limiting and merely set forth some of the manypossible embodiments for the claimed disclosure.

The term “continuous fibers” refers to fibers, filaments, yarns, orrovings (e.g., bundles of fibers) having a length that is generallylimited only by the length of the part. For example, such fibers mayhave a length greater than about 25 millimeters, in some embodimentsabout 50 millimeters or more, and in some embodiments, about 100millimeters or more. The continuous fibers may be formed from anyconventional material known in the art, such as metal fibers; glassfibers (e.g., E-glass, A-glass, C-glass, D-glass, AR-glass, R-glass,S1-glass, S2-glass), carbon fibers (e.g., graphite), boron fibers,ceramic fibers (e.g., alumina or silica), aramid fibers (e.g., Kevlar®marketed by E. I. duPont de Nemours, Wilmington, Del.), syntheticorganic fibers (e.g., polyamide, polyethylene, paraphenylene,terephthalamide, polyethylene terephthalate and polyphenylene sulfide),and various other natural or synthetic inorganic or organic fibrousmaterials known for reinforcing thermoplastic compositions, e.g.,spectra. Glass fibers and carbon fibers are particularly desirable foruse in the continuous fibers. Such fibers often have a nominal diameterof about 4 to about 35 micrometers, and in some embodiments, from about9 to about 35 micrometers. The tow or fibrous bundles must containuntwisted filaments. If desired, the fibers may be in the form ofrovings (e.g., bundle of fibers) that contain a single fiber type ordifferent types of fibers. Different fibers may be contained inindividual rovings or, alternatively, each roving may contain adifferent fiber type. For example, in one embodiment, certain rovingsmay contain continuous carbon fibers, while other rovings may containglass fibers. The number of fibers contained in each roving can beconstant or vary from roving to roving.

The term “long fibers” generally refers to fibers, filaments, yarns, orrovings that are not continuous and have a length of from about 0.5 toabout 25 millimeters, in some embodiments, from about 0.8 to about 15millimeters, and in some embodiments, from about 1 to about 12millimeters. The long fibers may be formed from any of the material,shape, and/or size as described above with respect to the continuousfibers. Glass fibers and carbon fibers are particularly desirable foruse as the long fibers.

Any of a variety of thermoplastic polymers may be employed to form thethermoplastic matrix in which the continuous and long fibers areembedded. Suitable thermoplastic polymers for use in the presentdisclosure may include, for instance, polyolefins (e.g., polypropylene,propylene-ethylene copolymers, etc.), polyesters (e.g., polybutyleneterephalate (“PBT”)), polycarbonates, polyamides (e.g., Nylon™),polyether ketones (e.g., polyetherether ketone (“PEEK”)),polyetherimides, polyarylene ketones (e.g., polyphenylene diketone(“PPDK”)), liquid crystal polymers, polyarylene sulfides (e.g.,polyphenylene sulfide (“PPS”)), fluoropolymers (e.g.,polytetrafluoroethylene-perfluoromethylvinylether polymer,perfluoro-alkoxyalkane polymer, petrafluoroethylene polymer,ethylene-tetrafluoroethylene polymer, etc.), polyacetals, polyurethanes,polycarbonates, styrenic polymers (e.g., acrylonitrile butadiene styrene(“ABS”)), and so forth.

Referring now to the drawings, wherein the depictions are for thepurpose of illustrating certain exemplary embodiments only and not forthe purpose of limiting the same, FIG. 1 schematically shows anexemplary extrusion system 100. The system 100 includes a first extruder101 containing a screw shaft 108 mounted inside a barrel 103. A heater110 (e.g., electrical resistance heater) is mounted outside the barrel103. During use, a first thermoplastic polymer feedstock 102 is suppliedto the extruder 101 through a hopper 106. The feedstock 102 may containlong fibers, may be free of long fibers, and/or such fibers may besupplied at another location (not shown), such as downstream from thehopper 106 and/or other feed ports.

The thermoplastic feedstock 102 is conveyed inside the barrel 103 by thescrew shaft 108 and may be heated by frictional forces inside the barrel103 and by the heater 110. Upon being heated, the feedstock 102 exitsthe barrel 103 through a barrel flange 114 and enters a die flange 116of an impregnation die 120, i.e., a melt extrusion die. A continuousfiber roving 105 or a plurality of continuous fiber rovings 105 aresupplied from a reel or reels 104 to die 120. The rovings 105 aregenerally kept apart a certain distance before impregnation, such as atleast about 4 millimeters, and in some embodiments, at least about 5millimeters. In one embodiment, a tension assembly 109 may be utilizedto impart a tension upon the rovings 105. The tension assembly 109 maybe implemented to provide a tension of an outside pull nature so as toeliminate twist in the rovings 105. Tensioning helps spread the tow to adesirable width to allow impregnation, supplies a desirable force toimpregnate any particular resin due to its viscosity and heat stabilityand finally provides a force that goes into twisting which also aids inremoving excess resin and impregnation. This tension applied to therovings 105 can range from a quarter of a pound to ten pounds ofresistance tension placed upon the rovings 105.

In various embodiments, the rovings 105 may be pre-heated in an oven 111before moved into the die 120. Pre-heating the rovings 105, removesresidual moisture from either the rovings 105 or the sizing on therovings 105. This oven 111 could be set at temperatures anywhere from200-degrees F. to 800-degrees F., depending on the properties of theparticular type of rovings 105, sizing of the rovings 105, and the speedat which the rovings 105 travel through the oven 111. Pre-heating allowsfor more desirous spreading and adhesion of the matrix resin to thereinforcement surface of the rovings 105. Subsequent or concurrent withpre-heating in the oven 111, the rovings 105 may be spread andpre-heated while traveling within an assembly 113 having alternatingpins with radial surfaces that further increase spreading and pre-heatof the rovings 105 at temperatures ranging from 150 F to 850 F dependingon the particular type of roving 105.

The feedstock 102 may further be heated inside the die 120 by heaters122 mounted in or around the die 120. The die 120 is generally operatedat temperatures that are sufficient to cause melting and impregnation ofthe thermoplastic polymer 102. Typically, the operation temperatures ofthe die 120 is higher than the melt temperature of the thermoplasticpolymer. When processed in this manner, the continuous fiber rovings 105become embedded in the polymer matrix, which may be a resin processedfrom the feedstock 102. The mixture is then extruded from theimpregnation die 120 to create a first extrudate 124.

A pressure sensor 112 may be used to monitor pressure near theimpregnation die 120 to allow control to be exerted over the rate ofextrusion by controlling the rotational speed of the screw shaft 108, orthe feed rate of the feeder. That is, the pressure sensor 112 ispositioned near the impregnation die 120 so that the extruder 101 can beoperated to deliver a preferable amount of molten polymer forinteraction with the fiber rovings 105. In various embodiments, thepreferable amount of resin is an amount to sufficient to be equallyspread across the rovings 105 at a percentage level that allows for thefull covering of the filaments surface within the reinforcement bundlewithout excess. By only applying a minimum amount at the step, thereremains potential for a secondary resin to be applied later to thisextrudate 124.

In one embodiment, after leaving the die 120, the extrudate 124 movesthrough a impregnation die assembly 115 having a series of alternating,heated, impregnation pins. These pins may also have convex and concavesurfaces to allow the polymer to move both in an x and y direction forthorough impregnation of the extrudate 124.

In various embodiments, the extrudate 124, or impregnated fiber rovings105, may then be moved through a cooling a rolling assembly 117 whichmay include a nip formed between two adjacent rollers 126 to enhancefiber impregnation and squeeze out any excess voids. The resultingconsolidated ribbon is pulled by tracks 128 mounted on rollers. Thetracks 128 also pull the extrudate 124 from the impregnation die 120and/or the impregnation die assembly 115 and through the rollers 126. Inone embodiment, the extrudate 124 is then twisted into a circular bundlewhich again aids in further impregnation and takes any excess resin anddisplaces it to the surface of the bundle. This impregnated cord ofreinforcement material may then be chilled to a temperature at which themolten polymer becomes solid.

The system 100 further includes a second extruder 131 containing a screwshaft 138 mounted inside a barrel 133. A heater 130 (e.g., electricalresistance heater) is mounted outside the barrel 133. During use, asecond thermoplastic polymer feedstock 122 is supplied to the secondextruder 131 through a second hopper 107. The feedstock 122 will containa secondary polymer that may be the same or different as the primarypolymer which could contain any number of additives (e.g., talc, mica,colorant, heat stabilizer, UV stabilizer, EMI shielding, nano-particles,short fibers, recycled material, etc.).

The second thermoplastic feedstock 122 is conveyed inside the barrel 133by the screw shaft 138 and may be heated by frictional forces inside thebarrel 133 and by the heater 130. Upon being heated, the feedstock 122exits the barrel 133 through a barrel flange 134 and enters a die flange136 of a closed die 140. The feedstock 122 may further be heated insidethe die 140 by heaters 122 mounted in or around the die 120. The die 140is generally operated at temperatures that are sufficient to causemelting to allow for over coating of the composite strand containing theprimary polymer and the continuous filaments. Typically, the operationtemperatures of the die 140 is higher than the melt temperature of thesecond thermoplastic polymer 122. In one embodiment, the operationtemperature of the second die 140 is less than a melt temperature of thefirst thermoplastic polymer 102, but higher that a melt temperature ofthe second thermoplastic polymer 122. The extrudate 124, from the firstdie 120 are supplied to the second die 140. The extrudate 124, whenprocessed in this manner, becomes layered with the second polymermatrix, which may include a resin processed from the feedstock 122. Themixture is then extruded from the impregnation die 140 to create asecond extrudate 148.

A pressure sensor 132 may be used to monitor pressure near the secondimpregnation die 140 to allow control to be exerted over the rate ofextrusion by controlling the rotational speed of the screw shaft 138, orthe feed rate of the feeder. That is, the pressure sensor 132 ispositioned near the impregnation die 140 so that the extruder 131 can beoperated to deliver a correct amount of resin for interaction with theextrude 124 from the first die 120.

After leaving the second impregnation die 140, the extrudate 148, mayenter an optional pre-shaping, or guiding section (not shown) beforeentering a nip formed between two adjacent rollers 144. Althoughoptional, the rollers 144 can help to consolidate the extrudate 148 intothe form of a ribbon (or tape), as well as enhance fiber impregnationand squeeze out any excess voids. In addition to the rollers 144, othershaping devices may also be employed, such as a die system. Theresulting consolidated ribbon 149 or cord is pulled by tracks 146mounted on rollers. The tracks 146 also pull the extrudate 148containing the continuous filaments from the impregnation die 140 andthrough the rollers 144. If desired, the consolidated ribbon 149 may bewound up at a section or chopped into LFT pellets in a chopper 150 inlengths ranging from ⅛ of an inch to one-inch-long pellets, but may varyaccording to preset parameters.

In operation, the first and second polymers, 102 and 122, respectively,may have a same or different chemistry, but may have two differingmolecular weights. The first polymer 102 may be selected due primarilyto its viscosity, heat stability, sizing adhesion promoters (maleicanhydride) and increased modulus needed to support the reinforcing fiberof a given length. In various embodiments, this first polymer 102 willbe of lower molecular weight and have low impact resistance. In variousembodiments, the first polymer 102 is selected to have high melt flow orlow viscosity, high modulus, optimum heat stability and low meltstrength. The additives to the first polymer 102 would contain but notbe limited to, chemical additions that enhance the interface and bondingto the reinforcing filaments and chemicals that would affect thecrystallinity growth rate of that polymer.

In one embodiment, the reinforcing fiber 104 would be spread into a flatband or rovings 105 through the use of tension and mechanical polishedrods or through the use of pressurized air. This reinforcing band 105may or may not need to be dried before entering a device which wouldheat the fiber to a desired temperature, this heating process allows forbetter impregnation of the first polymer 102. Upon exiting the heatingprocess, the reinforcing band of heated fiber would enter either aclosed or open die device, e.g., 120 that would allow for theintroduction of the impregnation polymer 102. This reinforcement, eithercoated or surrounded by an impregnation polymer, could then enter aseries of pins or rods that would further impregnate the reinforcingfiber strand. In the case of a closed die system, this impregnating towwould either: (1) exit through a sized orifice removing all but 30 to40% of the polymer from the extrude 124; or (2) in the case of an opendie system, only 30 to 40% of the polymer would be added to the fiberand then subsequent pins would allow for further impregnation. Then thisimpregnated strand will be formed, rolled or twisted into a cylindricalshape while the first polymer 102 is still molten. This strand willpreferably, but is not required to be, cooled to a given temperaturethrough the use of air, water or environmental conditions.

An exemplary extrude strand 124 exiting the die 120 is shown in across-sectional in FIG. 2B. As FIG. 2B shows, the strand 124 is formedof 30 to 40% of the first polymer 102, and 60% to 70% of the fiber 104.Unlike the known reinforced composite such as shown in FIG. 2A, thefibers 104 are fairly compacted with a minimum polymer 102 impregnated.The known reinforced composite such as shown in FIG. 2A generally have30% fiber and 70% polymer.

This extrude strand 124 would then enter an over coating die 140 where asecondary polymer 122, including any additives to the polymer 122, wouldbe applied to the exterior surface of the strand 124. This secondarypolymer 122 is added to the strand 124 to achieve a percentage thatbrings the overall strand to a desired fiber/polymer ratio. In oneembodiment, this strand 148 is then rapidly cooled and chopped to adesired length. In various embodiments, the second polymer 122 wouldgenerally be characterized by having a high molecular weight, lowviscosity, superior toughness and any additives that may enhance itsphysical and chemical characteristics. These additives could include,but are not limited to, talc (cost reduction), mica, colorants, heatstabilizers, UV inhibitors, flame retardants, EMI shielding, recycledpolymers, flow enhancers, nano-fill materials, short reinforcingfilaments, etc. In various embodiments, the extrude 124 into the seconddie 140 is formed of a 60% to 70% reinforcing fiber (fiberglass, carbon,aramid, HDPE, etc.), by weight, with little or no voids within thestrand. Thereafter, adding a second layer, surrounding the first layer,with a polymer 122 of the aforementioned attributes, inline anduninterrupted to the LFT process, that may produce a bi-polymer LFTpellet.

An exemplary extrude strand 148 exiting the die 140 is shown in across-sectional in FIG. 2C. As FIG. 2C shows, the strand 148 is formedof a first layer of the extrude strand 124 having 30 to 40% of the firstpolymer 102, and 60% to 70% of the fiber 104, and then a second layerformed of the second polymer 122, giving the total fiber to polymerratio between 30/70-40/60.

In one embodiment, due to the fully impregnated nature of the initialreinforcing strand with the initial polymer 102, the secondary polymer122 cannot displace the initial polymer 102 from the reinforcing strand.This initial polymer 102 then has a dominant effect on modulus andfilament adhesion, having a positive effect on the production speed ofthe process and the overall properties of the composite parts beingmolded. The secondary resin, although minimally affected by theproperties of the initial resin, could also be tailored to effect thedesired properties, performance and cost of the final composite article.In various embodiments, the extrude 124 is fully or near fully whet-out,so that the initial polymer 102 or the secondary polymer 122 cannotimpede either polymers performance. Thereafter, strands from the reel150 can enable subsequent products to be configured to allow thetailoring or “alloying” of specific composite properties that cannot beachieved through a traditional LFT process.

In various embodiments, the resulting consolidated ribbon 149 may becooled and chopped into pellets having a length of about 1″ or less.

The prepreg of the present disclosure may generally be used in a varietyof different applications and parts. For example, the prepreg may beformed into a profile, injection molded part, compression molded, part,etc. A “profile” is hollow or solid pultruded part that may possess awide variety of cross-sectional shapes, such as square, rectangular,circular, elliptical, triangular, I-shaped, C-shaped, U-shaped,J-shaped, L-shaped, slotted, etc. In hollow profiles, at least a portionof the interior of the profile is a voided space. The voided space mayoptionally extend the entire the length of the profile. The profiles mayalso be “lineal” to the extent that they possess a cross-sectional shapethat is substantially the same along the entire length of the profile,or they may have a varying cross-sectional shape, such as curved,twisted, etc.

The manner in which a profile may be formed from a prepreg can vary asis well known to those skilled in the art. One or multiple prepreglayers may be employed for forming the profile. For example, oneparticular embodiment of a system is shown in which a plurality ofprepregs are employed to form a profile. In this embodiment, theprepregs are provided in a wound package on a creel. The creel may be anunreeling creel that includes a frame provided with horizontal rotatingspindles, each supporting a package. A pay-out creel may also beemployed, particularly if desired to induce a twist into the fibers. Itshould also be understood that the prepregs may also be formed in-linewith the formation of the profile. In one embodiment, for example, theextrudate 148 exiting the impregnation die 148 from FIG. 1 may bedirectly supplied to the system used to form a profile.

A tension-regulating device may also be employed to help control thedegree of tension. The device may include inlet plate that lies in avertical plane parallel to the rotating spindles of the creel. Thetension-regulating device may contain cylindrical bars arranged in astaggered configuration so that the prepregs pass over and under thesebars to define a wave pattern. The height of the bars can be adjusted tomodify the amplitude of the wave pattern and control tension.

If desired, the prepregs may be heated in an oven having any of avariety of known configuration, such as an infrared oven, convectionoven, etc. During heating, the fibers are unidirectionally oriented tooptimize the exposure to the heat and maintain even heat across theentire profile. The temperature to which the ribbons are heated isgenerally high enough to soften the thermoplastic polymer to an extentthat the ribbons can bond together. However, the temperature is not sohigh as to destroy the integrity of the material.

Upon being heated, the continuous fiber ribbons may be provided to aconsolidation die to help bond together different ribbon layers, as wellas for alignment and formation of the initial shape of the profile.Although referred to herein as a single die, it should be understoodthat the consolidation die may in fact be formed from multipleindividual dies (e.g., face plate dies). The consolidation die mayreceive the prepregs so that it is guided through a channel of the diein a direction. The channel may be provided in any of a variety oforientations and arrangements to result in the desired reinforcementscheme. Within the die, the prepregs are generally maintained at atemperature at or above the melting point of the thermoplastic matrixused in the ribbon to ensure adequate consolidation.

If desired, a pultrusion die may also be employed that compresses theprepregs into the final shape for the profile. The configuration of thedie depends on the desired shape and properties for the resultingprofile. To form hollow profiles, the pultrusion die typically containsa mandrel within its interior so that the fiber material flows betweenthe interior surface of the die and the external surface of the mandrelto form the desired shape. Further, although referred to herein as asingle die, it should be understood that the pultrusion die may beformed from multiple individual dies.

One or multiple layers may be employed for forming the profile. In oneembodiment, for example, multiple layers are employed and initiallyspaced apart from each other in the vertical direction, e.g., aplurality of strands such as shown in FIG. 2C stacked upon one anotheror adjacent thereto. As they pass through respective channels of theconsolidation die, the widths of the layers are optionally ribboned tohelp prevent pressure wedges, and to keep the continuous fibers alignedand twist-free. Although not specifically shown, a mandrel may also beprovided in the interior of the consolidation die to help guide thelayers into contact with each other on at least one side of the profile.For example, one side of a prepreg layer and a side of another prepreglayer may be angled so that they contact each other and form a side of ahollow profile. The other side of the profile is, however, typicallyleft open within the consolidation die so that the long fiber materialcan be subsequently applied to the interior of the profile in thepultrusion die. When in the desired position, the prepreg layers arepulled into a pultrusion die as described above.

If desired, the resulting profile may also be applied with a cappinglayer to enhance the aesthetic appeal of the profile and/or protect itfrom environmental conditions. For example, such a capping layer may beapplied via an extruder oriented at any desired angle to introduce athermoplastic resin into a capping die. The resin may contain anysuitable thermoplastic polymer known in the art that is generallycompatible with the thermoplastic polymer used to form the profile.Suitable capping polymers may include, for instance, acrylic polymers,polyvinyl chloride (PVC), polybutylene terephthalate (PBT), ABS,polyolefins, polyesters, polyacetals, polyamids, polyurethanes, etc.Although the capping resin is generally free of fibers, it maynevertheless contain other additives for improving the final propertiesof the profile. Additive materials employed at this stage may includethose that are not suitable for incorporating into the continuous fiberor long fiber layers. For instance, it may be desirable to add pigmentsto the composite structure to reduce finishing labor of shaped articles,or it may be desirable to add flame retardant agents to the compositestructure to enhance the flame retarding features of the shaped article.Because many additive materials are heat sensitive, an excessive amountof heat may cause them to decompose and produce volatile gases.Therefore, if a heat sensitive additive material is extruded with animpregnation resin under high heating conditions, the result may be acomplete degradation of the additive material. Additive materials mayinclude, for instance, mineral reinforcing agents, lubricants, flameretardants, blowing agents, foaming agents, ultraviolet light resistantagents, thermal stabilizers, pigments, and combinations thereof.Suitable mineral reinforcing agents may include, for instance, calciumcarbonate, silica, mica, clays, talc, calcium silicate, graphite,calcium silicate, alumina trihydrate, barium ferrite, and combinationsthereof.

While not shown in detail herein, the capping die may include variousfeatures known in the art to help achieve the desired application of thecapping layer. For instance, the capping die may include an entranceguide that aligns the incoming profile. The capping die may also includea heating mechanism (e.g., heated plate) that pre-heats the profilebefore application of the capping layer to help ensure adequate bonding.

Following optional capping, the shaped part may be supplied to a coolingsystem as is known in the art. The cooling system may, for instance, bea vacuum sizer that includes one or more blocks (e.g., aluminum blocks)that completely encapsulate the profile while a vacuum pulls the hotshape out against its walls as it cools. A cooling medium may besupplied to the sizer, such as air or water, to solidify the profile inthe correct shape.

Following optional capping, the shaped part is then finally cooled usinga cooling system as is known in the art. The cooling system may, forinstance, be a vacuum sizer that includes one or more blocks (e.g.,aluminum blocks) that completely encapsulate the profile while a vacuumpulls the hot shape out against its walls as it cools. A cooling mediummay be supplied to the sizer, such as air or water, to solidify theprofile in the correct shape.

Vacuum sizers are typically employed when forming the profile. Even if avacuum sizer is not employed, however, it is generally desired to coolthe profile after it exits the capping die (or the consolidation orcalibration die if capping is not applied). Cooling may occur using anytechnique known in the art, such a vacuum water tank, cool air stream orair jet, cooling jacket, an internal cooling channel, cooling fluidcirculation channels, etc. Regardless, the temperature at which thematerial is cooled is usually controlled to achieve optimal mechanicalproperties, part dimensional tolerances, good processing, and anaesthetically pleasing composite. For instance, if the temperature ofthe cooling station is too high, the material might swell in the tooland interrupt the process. For semi-crystalline materials, too low of atemperature can likewise cause the material to cool down too rapidly andnot allow complete crystallization, thereby jeopardizing the mechanicaland chemical resistance properties of the composite. Multiple coolingdie sections with independent temperature control can be utilized toimpart the optimal balance of processing and performance attributes. Inone particular embodiment, for example, a vacuum water tank is employedthat is kept at a preset temperature range.

As will be appreciated, the temperature of the profile as it advancesthrough any section of the system of the present invention may becontrolled to yield optimal manufacturing and desired final compositeproperties. Any or all of the assembly sections may be temperaturecontrolled utilizing electrical cartridge heaters, circulated fluidcooling, etc., or any other temperature controlling device known tothose skilled in the art.

In various embodiments, a pulling device is positioned downstream fromthe cooling system that pulls the finished profile through the systemfor final sizing of the composite. The pulling device may be any devicecapable of pulling the profile through the process system at a desiredrate. Typical pulling devices include, for example, caterpillar pullersand reciprocating pullers. If desired, one or more calibration dies (notshown) may also be employed. Such dies contain openings that are cut tothe exact profile shape, graduated from oversized at first to the finalprofile shape. As the profile passes therethrough, any tendency for itto move or sag is counteracted, and it is pushed back (repeatedly) toits correct shape. Once sized, the profile may be cut to the desiredlength at a cutting station (not shown), such as with a cut-off sawcapable of performing cross-sectional cuts.

As will be appreciated, the particular profile embodiment describedabove is merely exemplary of the numerous designs that are made possibleby the present invention. Among the various possible profile designs, itshould be understood that additional layers of continuous and/or longfiber material may be employed in addition to those described above.

Example 1

PPG 113-4589 fiberglass roving was used as a reinforcement strand inthis example. The strand was tensioned to 2.7 lbs., spread, dried at 450degrees Fahrenheit and then subsequently heated to 550 degreesFahrenheit before entering an open film die for impregnation. A BraskemT12900C high crystallinity co-polymer polypropylene with 2.5% maleicanhydride was selected as the initial impregnation polymer for thisbi-polymer LFT process. This polymer was selected because of its highcrystallinity, high molecular weight EPR phase and very high flexuralmodulus, while having 110 MFI which would allow for high speedimpregnation. 30% of this matrix polymer was added to the strand. Thisstrand was then introduced to eight heated impregnation pins (520° F.).This thoroughly impregnated heated strand then enters a canted rollsystem which twists the fiber into a round cord like orientation. Thistwisting process will also increase fractionally, the length of thefiber in respect to the overall length of the final pellet. This strandis air cooled to roughly 200° F. This strand is then pulled through a ⅛″overcoat die where a Braskem Inspire 404 performance polypropylenepolymer filled with 5% carbon black colorant is wire coated on thesurface. This bi-polymer LFT pellet now contains a 30% overall fibercontent. This strand still moving at 150 fpm is then water cooled andchopped into W′ lengths.

Example 2

TORAY T300 24K carbon fiber roving was used as a reinforcement strand inthis example. The strand was tensioned to 3.2 lbs., spread, dried at 450degrees Fahrenheit and then subsequently heated to 600 degreesFahrenheit before entering an open film die for impregnation. A BASFUltramid 8202HS high melt flow, modified crystallinity nylon 6 wasselected as the initial impregnation polymer for this bi-polymer LFTprocess. This polymer was selected because of its viscosity, heatstabilized and high process ability. 40% of this matrix polymer wasadded to the strand. This strand was then introduced to eight heatedimpregnation pins (545° F.). This thoroughly impregnated heated strandthen enters a canted roll system which twists the fiber into a roundcord like orientation. This twisting process will also increasefractionally, the length of the fiber in respect to the overall lengthof the final pellet. This strand is air cooled to roughly 300° F. Thisstrand is then pulled through a ⅛″ overcoat die where a BASF UltramidBU501 extremely tough nylon 6 with high heat and chemical resistance, inaddition to low temperature performance, filled with 5% carbon blackcolorant is wire coated on the surface. This bi-polymer LFT pellet nowcontains a 30% overall fiber content. This strand still moving at 40 fpmis then air cooled and chopped into W′ lengths.

Example 3

DuPont Kevlar 9000 tex aramid yarn roving was used as a reinforcementstrand in this example. The strand was tensioned to 4.5 lbs., spread,dried at 200 degrees Fahrenheit and then subsequently heated to 400degrees Fahrenheit before entering an open film die for impregnation. AGrilamid TR amorphous polyamide 12 resin was selected as the initialimpregnation polymer for this bi-polymer LFT process. This polymer wasselected because of its amorphous nature, which provides excellentadhesion to the fiber interface, adhesion to the polymer is a typicalproblem with aramid fibers. 60% of this matrix polymer was added to thestrand.

This strand was then introduced to eight heated impregnation pins (450°F.). This thoroughly impregnated heated strand then enters a canted rollsystem which twists the fiber into a round cord like orientation. Thistwisting process will also increase fractionally, the length of thefiber in respect to the overall length of the final pellet. This strandis air cooled to roughly 200° F. This strand is then pulled through a ⅛″overcoat die where a Grilamid L polyamide 12 is wire coated on thesurface. This bi-polymer LFT pellet now contains a 20% overall fibercontent. This strand still moving at 140 fpm is then air cooled to 200degrees Fahrenheit and chopped into W′ lengths.

Example 4

Spectra 5900-5600 denier fiber roving was used as a reinforcement strandin this example. The strand was tensioned to 5 lbs., spread, dried atless than 150 degrees Fahrenheit and then subsequently heated to 180degrees Fahrenheit before entering an open film die for impregnation. ADow LDPE 9595 was selected as the initial impregnation polymer for thisbi-polymer LFT process. This polymer was selected because of its 50 MFIand melt temperatures of 230 degrees Fahrenheit which is 90 degreesFahrenheit less than the melting point of the fiber itself. 20% of thismatrix polymer was added to the strand.

This strand was then introduced to eight heated impregnation pins (240°F.). This thoroughly impregnated heated strand then enters a canted rollsystem which twists the fiber into a round cord like orientation. Thistwisting process will also increase fractionally, the length of thefiber in respect to the overall length of the final pellet. This strandis air cooled to roughly 100° F. This strand is then pulled through a ⅛″overcoat die where a Dow LDPE 1SOE is wire coated on the surface. Thispolymer was chosen for its high elongation to break, extreme toughnessand extremely low MFI. This fractional melt flow LDPE combined with thespectra fibers produces an extremely tough, ballistic resistant, cutresistant and low temperature moldable composite article. Thisbi-polymer LFT pellet now contains a 50% overall fiber content. Thisstrand still moving at 150 fpm is then air cooled and chopped into W′lengths.

Example 5

PPG 113/4588 E-glass fiber roving was used as a reinforcement strand inthis example. The strand was tensioned to 2.7 lbs., spread, dried at 450degrees Fahrenheit and then subsequently heated to 550 degreesFahrenheit before entering an open film die for impregnation. A BraskemT12900C high crystallinity co-polymer polypropylene with 2.5% maleicanhydride blended at 80% with 20% TOPAS 6017, was selected as theinitial impregnation polymer for this bi-polymer LFT process. Thispolymer and additives were selected because of its modulus enhancementto polyolefin resins. 30% of this matrix polymer was added to thestrand. This strand was then introduced to eight heated impregnationpins (520° F.). This thoroughly impregnated heated strand then enters acanted roll system which twists the fiber into a round cord likeorientation. This twisting process will also increase fractionally, thelength of the fiber in respect to the overall length of the finalpellet.

This strand is air cooled to roughly 200° F. and then pulled through a⅛″ overcoat die where a Braskem Inspire 404 performance polypropylenepolymer filled with 5% carbon black colorant is wire coated on thesurface. This hi-polymer LFT pellet now contains a 30% overall fibercontent. This strand still moving at 150 fpm is then air cooled andchopped into W′ lengths. This final polymer when molded compared toexample one will exhibit ten to fifteen percent higher modulus due tothe fact that the first polymer was designed as a polymer that wouldbetter adhere to the filament surface, thus supporting the filamentbetter and increasing modulus.

In one exemplary process for manufacturing a thermoplastic ribbon, thesystem 100 is modified so that the finished ribbon is completed afterthe tracks 128. In this modified system, a second resinous matrix is notproduced. Hence, the second extruder 131 and the die 140 are unnecessaryand may be excluded along with the supporting elements. The processbeings by presetting various operating parameters, thermoplastic ribbonspecifications preset; and selected material including the selectedreinforcing filament and polymer is loaded or otherwise readied.

Fibers may be selected for desired strength, ductility, abrasionresistance, elongation to break or the combination thereof that will beused as the strengthening filaments of the ribbon product itself. Insome embodiments, the reinforcing filament should be untwisted andminimally mingled together. The filament should have melting points,degradation points or flammability points, above 160 F. For example,products that requires high modulus (stiffness), e.g., ladies toe capsor heel reinforcements, carbon would be a good choice. In anotherexample, products where a high tensile strength and high ductility isdesirous, e.g., products used for strapping or banding packagestogether, a fiber such as Spectra 1000 (Highly elongated HDPE) may bedesirous. In another example, products where a high tensile strength andhigh ductility along with a higher temperature requirement are desirous,e.g., toe caps for industrial work boots, fibers such as an aramid orpara-aramid fiber could be used. These embodiments may also be desirouswhen cut resistances and adhesion to the leather would be important. Inanother example, products where a low cost, high strength and highmodulus system is desirous, fiberglass reinforcing filaments could beused, such as, e.g., in boat repairs or adhering layers of woodtogether.

A thermoplastic polymer may be selected to meet the low temperaturemelting demands and desired adhesion characteristics that are needed inthe final ribbon product. One or more polymers are selected from twobroad, general categories: (1) polymers that will not adhere or bond toother substrates but will adhere or bond to itself, e.g., Perstorp Capa6400; and (2) a polymer system that would primarily bond to othersubstrates. Both polymer types preferably become melted and tackybetween room temperature and 230 degrees F. In this way, the user candeploy the ribbon in his or her specific application, using hot water, ahair dryer or heat gun, an air activated thermal pack, ultrasonic ormicrowave to heat and activate the ribbon product without getting burnt.

Polymers that will not adhere or bond to other substrates but willadhere or bond to itself may be used in binding, tying, plugging andfastening systems together. Perstorp Capa 6400, for example, is a linearpolyester derived from caprolactone monomer that may be used in someembodiments.

Polymers that would primarily bond to other substrates may includeCovestro Desmomelt 530/540 (a flexible thermoplastic polyurethane). Thiswould provide excellent adhesion to the reinforcing filaments as well asprovides outstanding adhesion to a large number of materials, includingleather, textiles, wood, metals, etc. These products would primarily beused in bonding applications where adhesion to the substrate you arerepairing or bonding is needed.

Subsequent to selection of the fiber and the polymer, the process willbe the combining of the selected thermoplastic polymer and reinforcingfiber, in such a way that they are uniformly and intimately dispersedwithin one another.

In one exemplary operation, a user either inputs a desired number ofrovings or tows for a preferred width or thickness of the ribbon, or, inone embodiment, inputs a preferred width or thickness of the ribbon.Generally, reinforcing fibers are provided in bands, tows or rovingscontaining multiple filaments. Subsequent to selecting a fiber type, thesystem determines the number of rovings or tows that will be desired togive the final tape its desired width and thickness. Generally, thesetows or rovings come on bobbins, which usually contain several thousandyards of fiber. This selected number of rovings on their bobbins arethen loaded onto a creel system that allows them to be removed withoutadding twist to the fiber while under tension.

These fibers are then run through a serious of alternating, polishedpins or rods that have the effect of flattening and spreading theseroving bundles to a desired width and thickness. This band, containingmultiple rovings, is then drawn over heated pins that heat this band tothe molten temperature of the resin being applied. At this point, thisheated tensioned band, then has a molten stream of resin applied to thetop, bottom or both sides of this band to a desired and calculatedamount, usually based on weight percentages or volumes. This band willthen carry this resin forward through a series of heated polished pinsthat will allow for the molten polymer to be worked intimately anddispersed intimately throughout the reinforcing filaments containedwithin each separate roving. Through the last few of these heated pins,this molten polymer heated band is drawn through a slot that sets itsexterior dimensions. After exiting this slot, it immediately goes overone or more chill rollers that also contains a dimensional slot and theresin is cooled and the band becomes non-tacky, entering the pull rolls.The pull rolls are responsible for pulling the band through the processand setting the ultimate processing speed. After leaving the pull rollsthis cooled band of fiber and resin is then capable of being “Pancake”wound, onto master reels or spools. Any band width can be createdthrough the design of the machinery. In one embodiment, bands wider than48″ can be created by seaming two tapes together by the use of heat andpressure.

Example A

For this example a Dyneema SK75 Dtex 2640 HDPE roving was selected alongwith a Perstorp CAPA 6400 a high molecular weight linear polyesterderived from caprolactone monomer. Six ends of this reinforcing fiberwere loaded on to a creel and 1.5 lbs. of tension was applied to eachroving. These fibers were then drawn across a series of heated pinsspreading them to 1.5″ in width and heating them to 150 degreesFahrenheit. At this point they were introduced to a CAPA 6400 polymerstream, applying enough polymer to the top surface of this heated bandof reinforcing fiber at a rate to give the final impregnated tape a 50%by weight fiber, 50% by weight polymer, fully impregnated system. Theseimpregnated tows were drawn across several heated pins in which thepolymer was uniformly dispersed amongst all of the fiber filaments. Oncethis tow bundle was determined to be fully impregnated, it was narroweddown to a width of 1″ and a thickness of 0.015″. The fiber was thenintroduced to two more pins, uniformly setting these dimensions. Oncethese dimensions were set this “hot” impregnated tape was introduced totwo alternating chilled rolling cylinders, each with a 15/16″ groove, toset a width that when introduced to four more alternating cylindersallowed the tow to spread to 1″ in width. This chilled, impregnatedribbon was then taken up on master spools. These spools were thenremoved and placed on packaging equipment, of which spools of ribbonwere produced to a given length. These spools may be sold as a retailpackage into a broad range of markets including but not limited tosporting goods, camping, medical, dental, home improvement, plumbing,shoe/apparel, ladies undergarments, animatronics/robotics, orthotics andprosthetics, general repairs, boating and marine etc.

The unique feature of these substantially impregnated tapes is that whenthey are re-heated to 140 degrees Fahrenheit and placed in full contactwith another ribbon of the same chemistry, not necessarily the same sizeor dimension, and then cooled to room temperature they form a singleunit or structure with no discernable unit separation. They form asingle homogeneous part in any number of multiple units. When tworibbons are heated, applied in full contact with one another and cooledunder contact, the mechanical properties are at least twice themechanical properties of a single unit. Physical separation back intotwo units is difficult unless 138 degrees Fahrenheit in temperature isreapplied. They can be molded and fashioned an innumerable amount oftime, using this heating and cooling scenario. A single band, loopedupon itself, with an overlap of 1″, under these molding conditions andcooled, exhibited 26,000 psi in tensile strength. The tensile strengthcan be varied by simple adding or decreasing the number of rovingsplaced within the product and altering the resin flow to a givenpercentage.

Example B

Using the spooled ribbons from example A, these spools of ribbons wereplaced in a Dornier Tape Rapier Weaving Machine Type P1 Model PTST 2/ED4 25/40. This will produce a 48″ wide/1″ standard woven product. Thisproduct was then taken up on spools 48″ wide. These may or may not betaken to a double Teflon belt laminator, heated to 150 degreesFahrenheit, traveling at 10 ft/min, applying 10 psi. of pressure, thenimmediately leaving the heated zone into a room temperature zone wherethe product is cooled to 80 degrees Fahrenheit. This product was thentaken up on spools and could then be shipped for customers. One of manyapplications for this unique material would be the ability to constructa multiple ply moldable ballistic vest that is capable of being customfit to the military, law enforcement or security personnel that it isintended to protect. Other customizable ballistic components can also befashioned or molded to fit arms, legs, neck, groin, or any other areason the human body. A Second application could be simply molding multipleply's to construct or produce athletic padding across a wide range ofsports and activities. A third example would be taking multiple ply's ofthis material and molding it into a nonmetallic safety toe cap for theboot and shoe industry. A fourth example would be selling this materialinto a sheet form to the broad consumer industry including but notlimited to sporting goods, camping, medical, dental, home improvement,plumbing, shoe/apparel, ladies undergarments, animatronics/robotics,orthotics and prosthetics, general repairs, boating and marine etc.

Example C

For this example a Dyneema SK75 Dtex 2640 HDPE roving was selected alongwith a Perstorp Capa 6400 a high molecular weight linear polyesterderived from caprolactone monomer. An adhesion promoter such as Capa8502A or the Bayer Desmomelt system will be added at a given percentagefrom 1-99% by weight to the base polymer. These additives are added tothe base polymer to provide adhesion not only to themselves but to abase substrate that may be incompatible with the base polymer. Such astaking either the tapes or the woven tapes and repairing a polyethylenecanoe or kayak of which the base polymer would be incapable of doingwithout the adhesion promoters. Six ends of this reinforcing fiber wereloaded on to a creel and 1.5 lbs. of tension was applied to each roving.These fibers were then drawn across a series of heated pins spreadingthem to 1.5″ in width and heating them to 150 degrees Fahrenheit. Atthis point they were introduced to a CAPA 6400 polymer stream, applyingenough polymer to the top surface of this heated band of reinforcingfiber at a rate to give the final impregnated tape a 50% by weightfiber, 50% by weight polymer, fully impregnated system. Theseimpregnated tows were drawn across several heated pins in which thepolymer was uniformly dispersed amongst all of the fiber filaments. Oncethis tow bundle was determined to be fully impregnated, it was narroweddown to a width of 1″ and a thickness of 0.015″. The fiber was thenintroduced to two more pins, uniformly setting these dimensions. Oncethese dimensions were set this “hot” impregnated tape was introduced totwo alternating chilled rolling cylinders, each with a 15/16″ groove, toset a width that when introduced to four more alternating cylindersallowed the tow to spread to 1″ in width. This chilled, impregnatedribbon was then taken up on master spools. These spools were thenremoved and placed on packaging equipment, of which spools of ribbonwere produced to a given length and then could be distributed tocustomers. These spools could be sold as a retail package into a broadrange of markets including but not limited to sporting goods, camping,medical, dental, home improvement, plumbing, shoe/apparel, ladiesundergarments, animatronics/robotics, orthotics and prosthetics, generalrepairs, boating and marine etc.

One unique feature of these substantially impregnated tapes is that whenthey are re-heated to 140 degrees Fahrenheit and placed in full contactwith another ribbon of the same chemistry, not necessarily the same sizeor dimension, and then cooled to room temperature they form a singleunit or structure with no discernable unit separation. They form asingle homogeneous part in any number of multiple units. When tworibbons are heated, applied in full contact with one another and cooledunder contact the mechanical properties are twice the mechanicalproperties of a single unit. Physical separation back into two units isdifficult unless 138 degrees Fahrenheit in temperature is reapplied.They can be molded and fashioned an innumerable amount of time, usingthis heating and cooling scenario. A single band, looped upon itself,with an overlap of 1″, under these molding conditions and cooled,exhibited 26,000 psi in tensile strength. The tensile strength can bevaried by simple adding or decreasing the number of rovings placedwithin the product and altering the resin flow to a given percentage.

Example D

Using the spooled ribbons from example C, these spools of ribbons wereplaced in a Dornier Tape Rapier Weaving Machine Type P1 Model PTST 2/ED4 25/40. This will produce a 48″ wide/1″ standard woven product. Thisproduct was then taken up on spools 48″ wide. These may or may not betaken to a double Teflon belt laminator, heated to 150 degreesFahrenheit, traveling at 10 ft/min, applying 10 psi. of pressure, thenimmediately leaving the heated zone into a room temperature zone wherethe product is cooled to 80 degrees Fahrenheit. This product could thenbe taken up on spools for shipment to customers. One of manyapplications for this unique material would be the ability to constructa multiple ply moldable ballistic vest that is capable of being customfit to the military, law enforcement or security personnel that it isintended to protect. Other customizable ballistic components can also befashioned or molded to fit arms, legs, neck, groin, or any other areason the human body. A Second application could be simply molding multipleply's to construct or produce athletic padding across a wide range ofsports and activities. A third example would be taking multiple ply's ofthis material and molding it into a nonmetallic safety toe cap for theboot and shoe industry. A fourth example would be selling this materialinto a sheet form to the broad consumer industry including but notlimited to sporting goods, camping, medical, dental, home improvement,plumbing, shoe/apparel, ladies undergarments, animatronics/robotics,orthotics and prosthetics, general repairs, boating and marine etc.

Example E

For this example a Dyneema SK75 Dtex 2640 HDPE roving was selected alongwith a Dow ATTANE 4404G ultra low density polyethylene polymer. Six endsof this reinforcing fiber were loaded on to a creel and 1.5 lbs. oftension was applied to each roving. These fibers were then drawn acrossa series of heated pins spreading them to 1.5″ in width and heating themto 240 degrees Fahrenheit. At this point they were introduced to aATTANE 4404G polymer stream, applying enough polymer to the top surfaceof this heated band of reinforcing fiber at a rate to give the finalimpregnated tape a 50% by weight fiber, 50% by weight polymer, fullyimpregnated system. These impregnated tows were drawn across severalheated pins in which the polymer was uniformly dispersed amongst all ofthe fiber filaments. Once this tow bundle was determined to be fullyimpregnated, it was narrowed down to a width of 1″ and a thickness of0.015″. The fiber was then introduced to two more pins, uniformlysetting these dimensions. Once these dimensions were set this “hot”impregnated tape was introduced to two alternating chilled rollingcylinders, each with a 15/16″ groove, to set a width that whenintroduced to four more alternating cylinders allowed the tow to spreadto 1″ in width. This chilled, impregnated ribbon was then taken up onmaster spools. These spools were then removed and placed on packagingequipment, of which spools of ribbon were produced to a given length,which may then be distributed to customers. These spools are sold as aretail package into a broad range of markets including but not limitedto sporting goods, camping, medical, dental, home improvement, plumbing,shoe/apparel, ladies undergarments, animatronics/robotics, orthotics andprosthetics, general repairs, boating and marine etc. where a higherapplication temperature is required, in the range between 130 F and 180F.

A unique product that can be constructed from this material is toreplace metal or steel banding straps in the consumer and industrialpackaging and shipping markets. The unique feature of thesesubstantially impregnated tapes is that when they are re-heated to 255degrees Fahrenheit and placed in full contact with another ribbon of thesame chemistry, not necessarily the same size or dimension, and thencooled to room temperature they form a single unit or structure with nodiscernable unit separation. They form a single homogeneous part in anynumber of multiple units. When two ribbons are heated, applied in fullcontact with one another and cooled under contact the mechanicalproperties are twice the mechanical properties of a single unit.Physical separation back into two units is difficult unless 255 degreesFahrenheit in temperature is reapplied. They can be molded and fashionedan innumerable amount of time, using this heating and cooling scenario.A single band, looped upon itself, with an overlap of 1″, under thesemolding conditions and cooled, exhibited 26,000 psi in tensile strength.The tensile strength can be varied by simple adding or decreasing thenumber of rovings placed within the product and altering the resin flowto a given percentage.

Example F

Using the spooled ribbons from example E, these spools of ribbons wereplaced in a Dornier Tape Rapier Weaving Machine Type P1 Model PTST 2/ED4 25/40. This will produce a 48″ wide/1″ standard woven product. Thisproduct was then taken up on spools 48″ wide. These may or may not betaken to a double Teflon belt laminator, heated to 255 degreesFahrenheit, traveling at 10 ft/min, applying 10 psi. of pressure, thenimmediately leaving the heated zone into a room temperature zone wherethe product is cooled to 80 degrees Fahrenheit. This product could thenbe taken up on spools for shipment to customers.

Example G

A Toray 12K (12,000 filaments/roving) Carbon Fiber was selected for thisproduct, along with the Desmomelt polymer system. 4 ends of reinforcingfiber were loaded on the creel and 3 lbs. of tension were applied toeach roving. These carbon fibers were then spread over a series ofheated pins and heated to a temperature of 450 degrees Fahrenheit. Atthat temperature a melt stream of the Desmomelt polymer system wasintroduced to the top of these heated fibers at a rate to give the finalimpregnated tape a 60% by weight fiber, 40% by weight polymer, fullyimpregnated system. These impregnated tows were drawn across severalheated pins in which the polymer was uniformly dispersed amongst all ofthe carbon fiber filaments. Once this tow bundle was determined to befully impregnated, it was narrowed down to a width of 1″ and a thicknessof 0.012″. The fiber was then introduced to two more pins, uniformlysetting these dimensions. Once these dimensions were set this “hot”carbon impregnated tape was introduced to two alternating chilledrolling cylinders, each with a 15/16″ groove, to set a width that whenintroduced to four more alternating cylinders allowed the tow to spreadto 1″ in width. This chilled, carbon impregnated ribbon was then takenup on spools. These spools of ribbons were then removed and placed in aDornier Tape Rapier Weaving Machine Type P1 Model PTST 2/E D4 25/40.This will produce a 12″ wide/1″ standard woven product. This product wasthen taken up on spools 12″ wide. These spools were then taken to adouble Teflon belt laminator, heated to 240 degrees Fahrenheit,traveling at 10 ft/min, applying 10 psi. of pressure, then immediatelyleaving the heated zone into a room temperature zone where the productis cooled to 80 degrees Fahrenheit. This product could then be taken upon spools for shipment to customers. One of many applications for thisunique material is the ladies high fashion shoe industry, where thismaterial is used both as an adhesive layer and a stiffening layerbetween leather or other similar products, in the areas of toe caps,heals, soles and stilettos.

Example H

For this example a Dyneema SK75 Dtex 1760 HDPE roving was selected alongwith a Perstorp CAPA 6400 a high molecular weight linear polyesterderived from caprolactone monomer. Six ends of this reinforcing fiberwere loaded on to a creel and 1.5 lbs. of tension was applied to eachroving. These fibers were then drawn across a series of heated pinsspreading them to 1.5″ in width and heating them to 150 degreesFahrenheit. At this point they were introduced to a CAPA 6400 polymerstream, applying enough polymer to the top surface of this heated bandof reinforcing fiber at a rate to give the final impregnated tape a 50%by weight fiber, 50% by weight polymer, fully impregnated system. Theseimpregnated tows were drawn across several heated pins in which thepolymer was uniformly dispersed amongst all of the Dyneema fiberfilaments. Once this tow bundle was determined to be fully impregnated,it will be split back into its original rovings creating six smallerbands moving across the heated pins. We will continue to pull the fiberdownstream until the material is no longer molten. The fiber was thenpulled across a grooved, canted roller, twisting each individual rovingback to the last stationary heated pin, twisting them into a cylindricalthread, lace, cord or rod. This chilled, impregnated thread, lace, cordor rod was then taken up on spools. These threads, lace, cord or rodscan then be sold into either the consumer or industrial marketplaceincluding but not limited to the areas of sporting goods, camping,medical, dental, home improvement, plumbing, shoe/apparel, ladiesundergarments, animatronics/robotics, orthotics and prosthetics, generalrepairs, boating and marine etc. One unique application that theseindividual cords can service is that they can be braided into a rope,tether, leash, or strap that has the unique ability of when looped backon itself, heated, and then allowed to cool, eliminates the need for endfastening systems. This not only eliminates the need for end fasteningsystems but eliminates the weak point in all of these linear braidedapplications.

Example I

Using the spooled thread, lace, cord or rod from example H, these spoolsof ribbons were placed in a Dornier P1 Rapier Weaving Machine which isdesigned to weave thicker, tighter fabrics. This will produce a 48″ 12picks per inch standard woven product. This product was then taken up onspools 48″ wide. These may or may not be taken to a double Teflon beltlaminator, heated to 150 degrees Fahrenheit, traveling at 10 ft/min,applying 10 psi. of pressure, then immediately leaving the heated zoneinto a room temperature zone where the product is cooled to 80 degreesFahrenheit. This product could then be taken up on spools for shipmentto customers. These will usually produce much thicker sheets of materialwith lower mechanical properties.

Example J

For this example, a Dyneema SK75 Dtex 2640 HDPE roving was selectedalong with a Perstorp CAPA 6400 a high molecular weight linear polyesterderived from caprolactone monomer. Six ends of this reinforcing fiberwere loaded on to a creel and 1.5 lbs. of tension was applied to eachroving. These fibers were then drawn across a series of heated pinsspreading them to 1.5″ in width and heating them to 150 degreesFahrenheit. At this point they were introduced to a CAPA 6400 polymerstream, applying enough polymer to the top surface of this heated bandof reinforcing fiber at a rate to give the final impregnated tape a 50%by weight fiber, 50% by weight polymer, fully impregnated system. Theseimpregnated tows were drawn across several heated pins in which thepolymer was uniformly dispersed amongst all of the fiber filaments. Oncethis tow bundle was determined to be fully impregnated, it was narroweddown to a width of 1″ and a thickness of 0.015″. The fiber was thenintroduced to two more pins, uniformly setting these dimensions. Oncethese dimensions were set this “hot” impregnated tape was introduced totwo alternating chilled rolling cylinders, each with a 15/16″ groove, toset a width that when introduced to four more alternating cylindersallowed the tow to spread to 1″ in width. This chilled, impregnatedribbon was then coated on one or both sides with a Loctite highperformance middleweight bonding spray adhesive, creating an adhesivetape which can then be spooled. These spools were then removed andplaced on packaging equipment, of which spools of ribbon were producedto a given length, which may then be distributed to customers. Thesespools could be sold as a retail package into a broad range of marketsincluding but not limited to sporting goods, camping, medical, dental,home improvement, plumbing, shoe/apparel, ladies undergarments,animatronics/robotics, orthotics and prosthetics, general repairs,boating and marine etc. This and other adhesives are applied to ourribbon to produce an adhesive tape for the purposes of bonding it toitself until temperature can be applied to melt the matrix resin to forma single homogeneous unit. Adhesive is applied to both sides where anexterior cover of a varying material such as organic cloths, leathers orother plastics are needed for the particular application. A specificexample would be applying a woven cloth to the exterior and interior ofathletic padding for the purpose of moisture and perspiration wicking.

FIG. 6A-6C show an exemplary thermoplastic sleeve 200 placed over anobject 202. The object is exemplary. It is contemplated that the objectmay be most any tangible, physical object. The sleeve 200 may be formedof braided ribbons. In various embodiments, a tape, ribbon, or sheet canbe constructed by utilizing methods and techniques discussed hereinabove including, e.g., impregnation of low temperature resins withreinforcing fibers, and the taking those impregnated strands andsubsequently knitting, i.e., weaving, them into a ribbon. In oneembodiment, a tube may be braided such as shown in FIG. 6B and thenunder enough heat to melt the resin, then applying enough pressure tocollapse and consolidating the tubular structure, or consolidate theknitted structure. Thereby producing a ribbon that when reheated canmove in a three-dimensional manner, which may conform to the intricaciesof the human body including the human mouth and teeth. Thesethree-dimensional tapes or ribbons could be produced in almost limitlesssizes, thicknesses, and configurations. With either braiding orknitting, different fiber inputs could be utilized in a single tapeconstruction by simply altering, alternating, or mixing the bobbininputs utilized in constructing a braided or knitted product. The mixingor blending of different fiber inputs, such as carbon, HDPE, aramid,fiberglass, polyester, and others could be used to modify physicalproperties such as tensile strength, modulus, impact resistance,elongation and other physical characteristics.

For some medical applications, such as casts, splints, or boot formationfor prosthesis fittings, the braided tubular structure would not beconsolidated into a tape but rather left in its tubular form and thenconsolidated and fitted once slid on to what it is designed to reinforceor protect. Again, a combination of reinforcing filaments may be used toalter physical characteristics and properties.

Example I

First, 24 individual wound packages of 1/16″ wide, 0.003″ thick, HDPEfiber/caprolactone polymer at a 30% by weight fiber concentration, wereproduced using techniques described hereinabove. These inputs were thenloaded on to a braiding unit and a 1″ diameter braided tube was producedhaving a wall thickness of 0.006″. A 1000 ft. spool of this braidedtubular structure was pancake wound on a spool. This spool was thentaken and placed on a consolidation unit where this material was unwoundunder light tension, run through a IR oven where the tube was heated to160 degrees Fahrenheit. This heated braided structure continued througha series of Teflon coated rollers (male/female configuration) that areunder 20 psi of pressure. The female roller slot and opposing maleroller were machined with a 2″ flat configuration. A series of 10 ofthese rollers, 4″ in diameter each were placed in a line. They hadcooling passing through them to keep them at a nominal 40 degreesFahrenheit. This produced a braided tape 2″ in width and 0.120″ inthickness. This consolidated tape or ribbon was wound on to spools. Thistape can be used in everything from finger splinting material toselectively reinforcing pure caprolactone polymer sheet for additionalstrength and modulus.

Example II

First 16 packages of 1/16″ wide, 0.004″ thick, 675 yield E glassfiber/caprolactone resin at a 40% by weight fiber concentration wereconstructed. Next 16 packages of 1/16″ wide, 0.003″ thick 6K carbonfiber, 30% by weight fiber concentration were also constructed. Thesehelically wound packages were loaded onto a braiding machine in analternating configuration (carbon, glass, carbon, glass, etc,) and a ¾″tubular structure was braided having a wall thickness of 0.012″. Thismulti-reinforcement braided structure was then passed through the sameconsolidation unit as before except that the roller slots and opposingmale roller were cut to produce a 1½″ slot/tape. This tape/ribbon endedup 1½″ wide with a 0.020″ thickness. The tape had a modulus over 10times that tape in example I.

Example III

First 64 packages of 1/16″ wide, 0.004″ thick, HDPE fiber/caprolactoneresin at a 20% by weight fiber concentration. Next 128 packages of 1/16″wide, 0.003″ thick 6 k carbon fiber, 30% by weight fiber concentrationwere also constructed. Each of these materials were separately braidedinto a 4½″ diameter tube. Both materials were taken up into separaterolls. The braided HDPE material was the inner material (next to theskin) while the thicker carbon fiber material was the outer layer informing a socket over a stump while the other end was connected to aprosthesis for an amputee. Once stretched over the stump 140-degree heat(Fahrenheit) was applied until both layers were melted. The two layersare then melded together with simple hand pressure from fitting to thestump. Once cooled for 12 hours to allow the full crystallization of theresin you have a field ready prosthetic device without the need for alab or sending out material to be manufactured. If the patient is achild the prosthetic socket can be reheated and cooled to allow forgrowth of the child.

Example IV

First 24 packages of 1/32″ wide, 0.003″ thick HDPE fiber/caprolactoneresin at a 30% by weight fiber concentration. All 24 packages or inputswhere loaded onto a braiding unit and a ½″ diameter braided tube wasproduced. This braided tube was then passed through the same set ofconsolidation parameters as in Example 1, except that a 1″ wideconsolidated ribbon was produced. These consolidated ribbons are thensubsequently loaded onto a Dornier Rapier loom, 12 packages in the warpdirection and one package in the weft direction. A plain weave 12″ widebroad goods was at 100 pics or inches/min. This woven structure is thenpassed through a dual Teflon belt laminator having a heating zone set150 degrees Fahrenheit and a cooling zone at 50 degrees Fahrenheit.These belts were under 10 psi of pressure and moving at 10 ft./min. Thisproduced a continuous, solid, homogenous sheet that can be cut intodesired lengths and widths at any time. These sheets when reheated at140 F can be formed into any desired 3-dimensional shape, conforming toalmost any part of the human anatomy. These sheets and be laminatedtogether to add additional strength, modulus, and impact resistancewhere needed.

Example V

First 68 packages of 1/64″ wide, 0.005″ thick PET (polyester)fiber/caprolactone (polyester) resin at a 50% by weight, where loadedonto a braiding unit and a 1½″ braided tube was produced. A polyesterfiber was chosen for this application since very limited physicalattributes are needed. It acts as a carrier for the resin, it bonds verywell to the resin, and can be colored or tinted. This braided structurecan be slipped over any handle, grip, device, control lever, etc. Onceit is cut to desired length it can be heated to 140 F and then withsimple hand pressure from the user's grip (squeezed) and allowed to coolunder grip pressure an extremely custom grip has been formed exactly tothe user's hand.

Example VI

First 136 packages of the same material in Example 5 are braided into a2½′ tube. This tube is then stretched over any revolver up to themid-point of the trigger guard and below or up to the hammer. Thematerial is then heated with a blow dryer or heat gun to a temperatureof 140F and then allowed to cool. Once cooled the braided tube is cutoff at the barrel termination. Attach any belt loops or clips and acustom fit holster has been created.

While the foregoing disclosure discusses illustrative embodiments, itshould be noted that various changes and modifications could be madeherein without departing from the scope of the described embodiments asdefined by the appended claims. Accordingly, the described embodimentsare intended to embrace all such alterations, modifications andvariations that fall within scope of the appended claims. Furthermore,although elements of the described embodiments may be described orclaimed in the singular, the plural is contemplated unless limitation tothe singular is explicitly stated. Additionally, all or a portion of anyembodiment may be utilized with all or a portion of any otherembodiments, unless stated otherwise.

The invention claimed is:
 1. A method for forming a thermoplasticprepreg, the method comprising: supplying continuous fibers to a firstextrusion device; supplying a first thermoplastic feedstock to the firstextrusion device, wherein the feedstock comprises a first thermoplasticpolymer; pre-heating, tensioning, and spreading the continuous fibers;extruding the continuous fibers and the first feedstock within animpregnation die to form a first extrudate in which the continuousfibers are embedded with a matrix of the first thermoplastic polymer;twisting the first extrudate; supplying a second thermoplastic feedstockto a second extrusion device, wherein the second feedstock comprises asecond thermoplastic polymer; and extruding the first extrudate and thesecond thermoplastic feedstock within an impregnation die to form asecond extrudate in which the second feedstock forms a layer around thefirst extrudate, while the first extrudate is twisted and under tension.2. The method of claim 1, wherein the continuous fibers constitute fromabout 30 to about 40 wt. % of the prepreg, the first polymer constitutefrom about 30 wt. % to about 40 wt. % of the prepreg, and the secondpolymer constitute from about 30 wt. % to about 40 wt. % of the prepreg.3. The method of claim 1, wherein the continuous fibers, include glassfibers, carbon fibers, or a combination of glass and carbon fibers. 4.The method of claim 1, further comprising: cooling the first extrudate;and chopping the second extrudate into a pellet.
 5. The method of claim1, wherein the second thermoplastic feedstock comprises talc material.6. The method of claim 1, wherein the second thermoplastic feedstockcomprises at least one of mica and fiberglass.
 7. The method of claim 1,wherein the second thermoplastic feedstock comprises at least one ofcopper and nickel particulate.